Digestive system ↗Droplets enter duodenum
Gastric mixing begins dispersion while nutrient sensing coordinates pancreatic and gallbladder secretion.
DIGESTIVE / FAT · BILE · CHYLOMICRONS
Hydrophobic cargo needs
a transport strategy.
Bile acids and lipase make dietary fat accessible. Enterocytes rebuild and package long-chain lipid into ApoB-48 chylomicrons, which travel through lymph before blood and return to the liver as remnants.
12-STAGE ROUTE
Intestine → lymph
→ blood → liver.
Chylomicrons carry dietary lipid; VLDL carries primarily liver-packaged triglyceride. Both use LPL but have different ApoB scaffolds and origins.
Bile acids emulsify
Amphipathic bile components stabilize a larger lipid-water interface for enzyme action.
Lipase hydrolyzes triglyceride
Pancreatic lipase with colipase releases free fatty acids and monoacylglycerol.
Mixed micelles approach cells
Bile-acid micelles ferry hydrophobic digestion products across the unstirred water layer.
Lipid enters enterocytes
Fatty acids, monoacylglycerol, cholesterol and fat-soluble vitamins cross the apical interface.
Triglyceride is rebuilt
Endoplasmic-reticulum enzymes re-esterify long-chain fatty acids into triglyceride.
ApoB-48 gains cargo
Microsomal transfer processes lipidate ApoB-48 to assemble nascent chylomicrons.
Particles enter lacteals
Large chylomicrons enter intestinal lymphatic capillaries rather than portal blood capillaries.
Lymph joins venous blood
The thoracic duct delivers chylomicrons into venous circulation.
LPL unloads triglyceride
Capillary lipoprotein lipase releases fatty acids for muscle oxidation or adipose storage according to context.
Particles become remnants
Triglyceride depletion leaves smaller particles enriched in cholesterol and remnant-associated apolipoproteins.
Liver clears remnants
Hepatic receptor pathways remove chylomicron remnants, closing the dietary route.